Human T cell subset ratio quantitation by 51Cr release: assessment of a new technique

A method for T cell subset ratio quantitation is described. This technique makes use of monoclonal antibodies 66.1 (OKT4 equivalent) and 51.1 (OKT8 equivalent) in complement-dependent cytotoxicity. The percentages of 51Cr release with these 2 reagents from peripheral blood lymphocyte targets were used to calculate the ratio. It is simple, inexpensive, and can be used for large numbers of samples, but is less accurate when compared with the microscopic technique in immunofluorescence. It may serve as a screening test in certain clinical situations where there is need to determine the T4/T8 ratio.